Power actuator with pilot control



Feb. 12, 1952 SMALL 2,585,507

POWER ACTUATOR WITH PILOT CONTROL Filed June 25, 1949 3 Sheets-Sheet l INVEN TOR. [kwzmcx B. SMALL Feb. 12, 1952 F. B, SMALL POWER ACTUATOR WITH PILOT CONTROL s Sheets-Sheet 2 Filed June 23, 1949 JTVVENTOR. il eszznalck B. SMALL I fin Feb. 12, 1952 F. B. SMALL 2,585,507

POWER ACTUATOR WITH PILOT CONTROL Filed June 23, 1949 3 Sheets-Sheet s l INVENTOR. P 1%DRICK B. SMHZL 1 23 24 |i In BY WNW. I I 71).

Patented Feb. 12, 1952 Frederick B. Small, Water-100.171. Y., assignorto. Seneca Falls Machine Company, SenecaFalls. N. 2., av corporation of Massachusetts.

Application June23, 1949, Serial No. ll00,905

8; Qlaims, (Cl. 7.4 -3:88-)- This: invention relates to a. driving mechanism in, which a continuously rotated power member may be rendered operative or inoperati-ve with respect to a member to be driven, by the functioning of a relatively small pilot or control device.

In the preferred construction, a continuously rotated power shaft is provided, which power shaft may be coupled to turn an output shaft in either directionas determined by the pilot or control device.

It is the general object of my invention to provide an improved construction by which the powershaft may be selectively connected to the output shaft under the control of the pilot device and through alternative driving mechanisms. The pilot device in my improved actuator does not function to drivethe output shaft direct but operates only under very light load toselectively connect the power shaft to the output shaft.

I also provide a construction in which a driving member or members continuously rotate in one direction and maybe selectively connected under pilot control to turn the output shaft in either direction.

My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawings, in which Fig. 1 is a'sectional plan view of my improved power actuator;

Fig. 2 is a sectional elevation, taken along the line 2-2 in Fig. 1, and with certain parts omitted;

Figs. 3 and 4 are detail sectional views, taken along the lines 3-3 and 4--4 in Fig. 1;

Fig. 5 is a diagrammatic view illustrating the application of my invention to contourlathe operation; and

Fig. 6 is a sectional plan view showing a mod-.- ified construction.

Referring to Figs. 1 to 4, my improved power actuator in its preferred form comprises a casing C supporting an input or power shaft H! which may be continuously rotated by a motor M (Fig. 5), or which may be rotated from any other convenient source of power. An output shaft [5 is also mounted in the casing C and is normally stationary but is rotated in a se lected direction when coupled to the power shaft I!) through the control device to be described.

One application of this invention is illustrated in Fig. 5:, in which the invention is. shown as controllin the transverse position of a lathe tool. T- with respect to a rotated piece of work asv in a contour lathe. The tool T" is mounted on a cross. slide 20 slidable crosswise on a. carriage. 22 which is moved longitudinally of the work on guideways 2:3, and 24.-

A pattern plate P is mounted in fixed position and coacts with a detector or follower 25 pivoted at 2-6 on the cross slide 20 and having an insulated index arm 21 connected to a, line wireL.

The free end ofthe arm 2'! makes selective contacts. with terminals 30 and 3| which are connected to, a relatively. small control motor M'- through wires 32- and 3-3. The motor M is also connected to a second line wire L.- and is of the reversible type which will be rotated clockwise or anti-clockwise according as one or the other of the contacts is engaged by the arm 21 under control of the pattern plate P. Y

The motor M is connected through reduction gearing to a control shaft 40 rotatably mounted in a'suitable bearing secured to the front: of the casing C. The output shaft I5: is shown as provided with a pinion 42 engaging a rack 44 mounted on the carriage 22.

The operation of this illustrative mechanism may be-briefiy described as follows:

As the carriage 22' is moved longitudinally along the guideways 23 and 24, the detector or follower 25 followsthe contour of the fixed pat.- tern plate P. As the contour changes, the arm 21 swings to the right or left to engage one or the other of the contacts an and 3|; This causes the motor M" to rotate the control shaft 40 either clockwise or anticlockwi'se. This movement of the shaft 40 then causes the power shaft Ill to rotate the output shaft l5 and pinion 42- through mechanism to be described, thus moving the tool -'-I- toward or away from the work W under the controlof the pattern plate P, detector 25 and motor M. 7

It will be understood that the application of the invention shown in Fig. 5 andabove' de-.- scribed is illustrative only, and that the invention is well adapted for more general application.

Having made cleara desired result to be ob.- tained by use of my improved power actuator, the details of construction of the power actuator are as follows:

Referring particularly to Figs. 1 and 2, the power shaft. H1 is mounted in bearings 50 in the ends of the casing C and continuously rotates a pair of drums 52 and 54 mounted thereon.

A bevel gear 55 is mounted atthe left; of ,the

drum 52 as viewed in Fig. 2, and a similar but oppositely facing bevel gear 56 is mounted at the left of the drum 54. The gears 55 and 56 are freely rotatable on bearings 51 and 58 sup-ported by the shaft II). A third bevel gear 65 (Fig. 1) is mounted onthe inner end of the control shaft 40 and meshes with both bevel gears 55 and 55.

Rotation of the shaft 4'!) and bevel gear 6!] will thus cause both driven bevel gears 55 and 56 to be correspondingly rotated but in opposite directions, with one of the driven gears turning clockwise and the other anti-clockwise.

Additional bevel gears 62 and 64 are positioned adjacent the right-hand ends of the drums 52 and 54 and are freely rotatable on bearings 61 and 68, also supported on the shaft III. The gears 62 and 64 engage a bevel gear H! mounted on the inner end of the output shaft I and secured thereto.

'A tapered flat driving band 80 (Fig. 1) loosely encircles the drum 52 and has its wide end 85a attached to a bracket HI mounted on the adjacent face of the bevel gear 62. The narrow end 80b of the band 88 is secured to an arm 82 extending laterally from a flat disc 84 which is frictionally mounted on a bearing shoulder 85 (Fig. 2) on the inner face of the bevel gear 55.

A perforated cage 8'! (Figs. 1, and 2) is secured to the inner face of the gear 55 and encloses the spiral band 80. The band 80 preferably has a thin cork lining 88 (Fig. 4) which engages the drum '52 but normally has slight clearance.

' An arm 90 (Fig. 1) projects laterally from the disc 84 and is engaged by an adjusting screw 9! (Fig. 4) mounted in a lug 92 projecting from the side of the cage 81. A spring 94 holds the arm 90 firmly in engagement with the end of the screw 9!. One end of the spring 95 is connected to a pin 95 also mounted in the end of the cage 81.

A similar band IE0 is mounted within a cage IUI supported by the bevel gear 56, and the wide end IIlIia of the band IE0 is connected to a bracket mounted on the loose bevel gear 64, the details a band 85 or the band I00 to its associated drum 52 or 55 and to thereby effect power-actuated movements of the output shaft I5 corresponding to the movements of the control shaft 40 but without imposing any substantial load on the controlshaft. r

, In the construction shown'in Figs. 1 to 4, the

movement of the output shaft I5 will be in the opposite direction to the movement of the control shaft 40, but in the modified construction shown in Fig-6, the control and output shafts rotate in the same direction.

In this modification, a single drum II 0 is secured to a power shaft III rotatable in bearings in a casing C2 and continuously rotated by a motor M2. Gears I I2 and H4 are loosely mounted on the shaft III and engage gears H6 and HT on countershafts I I8 and I I9.

Bevel gears I and HI are mounted on the countershafts IIS and H9 respectively and both engage a third bevel gear I22 on the output shaft I25. Acontrol shaft I is mounted in a hearing in the casing C2 and rotates a bevel gear I3I mounted between and engaging bevel gears I32 and I33 freely rotatable on bearings concentric with the drum I00 but spaced therefrom.

Spiral bands I56 and I II loosely surround op- .posite end portions of the drum H0 and are connected between the gears H2 and I32 and between the gears lid and I33 respectively. The details of construction of the bands I50 and I 4| and their associated parts may be identical with the construction of the corresponding parts shown in Figs. 1 to a. a

The operation in this modification is similar to that of the construction shown in Figs. 1 to 4. Angular displacement; of the control shaft I30 rotates the gears I32 and I33 in opposite directions and tightens one or the other of the bands I and I II on the drum IIU. Resultant rotation' of the gear-H2 or the gear H4 is then transmitted through itsassociated countershaft to the output shaft I25, which in this case is rotatedin the same direction as the displacement of the control shaft I35.

Having, thus described my invention and th advantages thereof, I do not wish to be limited to the details herein disclosed; otherwise than as i set forth in the claims, .but what I claimis:

mounted concentric with the shaft I0 but free I therefromand normally stationary. If the control shaft 4'0 is displaced angularly in either direction, the bevel gears and 56 will be similarly displaced but in opposite directions.

Assuming that the, control shaft 40. is displaced clockwise, the bevel gear 55 will be similarly displaced clockwise, and the band 80 will be tightened about thedrum 52.--- The drum 52 will then turn the band 8i] and the bevel gear 62 in the same direction and to the same l.-A power actuator comprising a continuously rotated power shaft, an- -output shaft, powertransmitting means mounted on and-continuously rotated by said power shaft and comprising axially-spaced cylindrical operative portions rotated in the samedirection, aspiral band loosely encircling one of said operative portions, gearing connecting one end of said spiral band to said output shaft, 2. second spiral band loosely encircling the second operative portion, reverse gearing connecting one end of said second spiral band to said output shaft, a normally-stationary pilot device, and connections from said pilot device to the second end of each band, said pilot device being effective to tighten a selected band on its associated operative portion by rotary movement of said pilot device in a selected direction, and said power shaft and transmitting means being effective through saidselected band and associated gearing to turn said output shaft in a coordinated direction untilmovement of said pilot device ceases and until the selected band is loosened by further turning movement of said transmitting means.

2. The combination in a power actuator as set In-forth in claim-1, in which a hollow cylindrical cage encloses each band and limits the expansion and clearance thereof, and in which means is provided to connect said cage to the normallystationary pilot device and to cause said cage to rotate with said pilot device when the pilot device is operative.

S. The combination in a power actuator as set forth in claim 1, in which said pilot device comprises a normally-stationary control shaft, and selectively-operative automatic means to rotate said control shaft in an indicated direction.

4. The combination in a power actuator as set forth in claim 1, in which the pilot device and its operative connection comprises a control shaft, a pair of gears mounted coaxially with said power shaft but free therefrom and each gear being connected to the second end of one of said bands, and a gear connection from said control shaft effective to rotate said pair of gears in unison and in the same selected direction as determined by the direction of rotation of said control shaft.

5. The combination in a power actuator as set forth in claim 1, in which the pilot device comprises a. control shaft, 9. pair of oppositely-fac- 6 tions from said bands to the output shaft comprises a pair of gears loosely mounted concentric with said power shaft and each connected to the first mentioned end of one of said bands, and both of said gears being connected to positively rotate said output shaft in a selected direction.

7. The combination in a power actuator as set forth in claim 1, in which the spaced portions of the power-transmitting means are axially aligned parts of a single driving drum.

8. The combination in a power actuator as set forth in claim 1, in which the spaced portions of the power-transmitting means are axially aligned parts of a single driving drum, and in which the means operatively connecting the pilot device and said bands has supporting structure spaced transversely from and independent of said power shaft and transmitting means.

FREDERICK B. SMALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

